Department of Chemistry, Imperial College London, London, SW7 2AZ, United Kingdom.
Phys Chem Chem Phys. 2010 Dec 28;12(48):15725-33. doi: 10.1039/c0cp01757d. Epub 2010 Nov 16.
Direct quantum dynamics simulations were performed to model the radiationless decay of the first excited state S(1) of fulvene. The full space of thirty normal mode nuclear coordinates was explicitly considered. By default, ultrafast internal conversion takes place centred on the higher-energy planar region of the S(1)/S(0) conical intersection seam, giving the stepwise population transfer characteristic of a sloped surface crossing, and leading back to the ground state reactant. Two possible schemes for controlling whether stepwise population transfer occurs or not-either altering the initial geometry distribution or the initial momentum composition of the photo-excited wavepacket-were explored. In both cases, decay was successfully induced to occur in the lower-energy twisted/peaked region of the crossing seam, switching off the stepwise population transfer. This absence of re-crossing is a direct consequence of the change in the position on the intersection at which decay occurs (our target for control), and its consequences should provide an experimentally observable fingerprint of this system.
直接量子动力学模拟被用来模拟富烯的第一激发态 S(1)的无辐射衰减。完全考虑了三十个正则模核坐标的空间。默认情况下，超快内转换发生在 S(1)/S(0) 锥形交叉缝的高能平面区域中心，给出了具有倾斜表面交叉特征的逐步种群转移，并导致回到基态反应物。探索了两种控制是否发生逐步种群转移的可能方案-改变初始几何分布或光激发波包的初始动量组成。在这两种情况下，成功地诱导了在交叉缝的低能扭曲/峰值区域发生衰变，从而关闭了逐步种群转移。这种没有再穿越的情况是由于衰变发生的交点位置的变化（我们控制的目标）的直接结果，其后果应该为该系统提供一个可实验观测的指纹。
